Meningitis: Limited Vaccine Supply Threatens Response to Epidemics
More on Meningitis
Photo © Vanessa Vick
Barely two months into Africa's dry season, there are several countries facing severe outbreaks of meningitis. Doctors Without Borders/Médecins Sans Frontières (MSF) is already responding to epidemics in the Democratic Republic of Congo, southern Sudan, and northern Uganda. All three countries are in the southern tip of Africa's so-called "meningitis belt." This region, which is highly prone to epidemics, has 300 million inhabitants and stretches from Senegal in the west to Ethiopia in the east. Yet there is a very limited supply of vaccines. Dr. Cathy Hewison, MSF's meningitis specialist, answers questions about the risks for a wide-scale epidemic this year and the current availability of vaccines.
What is Meningitis?
Meningococcal meningitis is a contagious and potentially fatal infection of the brain membrane. It is caused by various strains, or serogroups, of the Neisseria meningitidis bacterium. Strains A, B, C, Y and W135 are the most common. Infected people often carry the disease without showing symptoms, and spread the bacteria to others when they cough or sneeze.
Cause: Bacterium Neisseria meningitidis. Strains A, B, C, Y, and W135 are the most common. Infected people typically carry the disease without showing symptoms and spread the bacteria through coughing and sneezing.
Symptoms: Meningitis causes sudden and intense headaches, fever, nausea, vomiting, photophobia, and stiffness of the neck. Death may occur within hours of the onset of symptoms.
Prevalence: Meningitis occurs sporadically throughout the world, but the vast majority of cases and deaths are in Africa. Epidemics regularly hit countries in the area referred to as the African "meningitis belt," which stretches across the continent from Senegal to Ethiopia. The total population at risk in these countries is around 300 million.
Treatment: Without treatment, bacterial meningitis kills up to 50 percent of infected people. Even if the disease is diagnosed early and treated with appropriate antibiotics, such as chloramphenicol or ceftriaxone, the case fatality rate remains 5 to 10 percent. As many as one out of five survivors will suffer from neurological after-effects such as deafness or mental retardation.
© Vanessa Vick
Vaccination: Timely mass vaccinations are the most effective means of limiting the spread of epidemics. The World Health Organization (WHO) has estimated that mass immunizations have managed to prevent up to 70 percent of expected cases in individual meningitis outbreaks in Africa.
Source: World Health Organization
Cold Chain: Preserving Vaccines in the Field
© Vanessa Vick
Many vaccines, such as those for measles, polio, and meningitis, must be kept frozen or within a constant temperature range or they will lose their effectiveness. This situation calls for what is commonly known as a "cold chain."
A cold chain is a continuous system of conservation and distribution of vaccines, at a precise temperature, from the factory to the field. MSF has developed a vaccination kit that has enough supplies for five teams to immunize 10,000 people. Included in this kit are ice packs, coolers, generators, gas-powered refrigerators, freezers, and thermometers to maintain the cold chain.
Setting up a large-scale meningitis vaccination program has enormous logistic implications, the vaccines must be procured from suppliers, the "cold chain" must be set up, and extra emergency field volunteers must be deployed.
© 2013 Doctors Without Borders/Médecins Sans Frontières (MSF)